Sewing machine balancing



June 19, 1956 H. HACKLANDER SEWING MACHINE BALANCING 2 Sheets-Sheet l Filed Feb. 5, 1954 WITNESS @D June 19, l956 H` HACKLANDER SEWING MACHINE BALANCING 2 Sheets-Sheet 2 Filed Feb. f5, 1954 )NI/ENTOR. Hans Hack/ander ATTORNEY United States Patent O SEWING MACHINE BALANCING Hans Hacklander, South Sterling, N. J., assigner to The Singer Manufacturing Company, Elizabeth, N. J., a corporation of New Jersey Application February 3, 1954, Serial No. 407,832

3 Claims. (Cl. 112-'220) The present invention relates to sewing machines. and has for a primary object to provide means for dynamically balancing the same to reduce undesirable vibrations thereof incident to operation of the machine. More specifically, it is an object of this invention to provide a balancing means including an independently actuated counterweight that may be readily applied to existing machines.

Having in mind the above and other objects that will be evident from an understanding of this disclosure, the invention comprises the devices, combinations and arrangements of parts as illustrated in a preferred embodiment of the invention which is hereinafter set forth-in such detail as to enable those skilled in the art readily to understand the function, operation, construction and advantages of it when read in conjunction with they accompanying drawings in which:

Fig. l is a rear elevation View, partly in section,.of a machine embodying the invention.

Fig. 2 is a fragmentary sectional view taken substantially on the line 2--2 of Fig. l.

Fig. 3 is a rear elevation View of the machine illustrated in Fig. l.

The machine illustrated in the drawings which .is of the hosiery-seamer type is substantially as disclosed in my prior U. S. Patent No. 2,277,970, March 31, 1942, to which patent reference may be had for a more complete description thereof. The machine is herein d'isclosed only insofar as is necessary to provide a full understanding of the present invention.

With reference to the drawings, there is provided a sewing machine having a frame 1 and a main-shaft 2 journaled transversely thereof in suitable bushings 3 and 4 which are fixed in enlarged bosses 5 in the opposed side walls of the frame 1. The ends of the shaft 2 extend outwardly of the frame 1 and have fixed thereto a balancewheel 6 and a combined balance-Wheel and belt-pulley 7 having a belt-groove S. A belt (not shown) is 4designed to be entrained about the belt-pulley 7 for the purpose of connecting the machine to a source of power for driving the same.

Fixed to the shaft 2 is an adjustable eccentric 9, the eccentric element of which is embraced by the strap portion of a .pitman 10. The free end of the pitman 10 is pivotally connected to one arm 11 of a bell-crank lever having a hub 12 that is loosely mounted on a pivot rod 13 arranged transversely of the frame 1 parallel to the shaft 2 and carried by the opposed side walls of the frame. The other arm 14 of the bell-crank lever is connected by a link 15 to the actuating arm 16 of a one-way clutch 17 which is operatively associated with a feed-shaft 18 for imparting actuation to one feed-cup (not shown) and includes a gear 19 for imparting actuation to the other feed-cup (not shown), in a manner such as disclosed in my above mentioned patent. It will be seen that intermittent one-way rotation is imparted to the feedcups upon rotation of the shaft 2.

There is formed in the shaft 2 a crank 20 connected ICC to. one end of a link 21 having its other end pivotally connected to one arm v22 of a bell-crank lever which includes a hub 23 loosely mounted for oscillation upon a pivot rod (not shown) carried by spaced lugs (also not Shown) formed in the frame 1. The other arm 24 of the bell-crank lever is connected by means of a link 25 to a lug 26 depending from a collar 27 fixed to a needle-bar 28 which is journaled in the frame 1 for horizontal reciprocation in a direction normal to the axis ofthe shaft 2. The above structure is all fully disclosed in my prior Patent No. 2,277,970, to which reference may be had for a complete disclosure of the same. In the above manner, axial reciprocation is imparted to the needle-bar 28 upon rotation of the shaft 2.

Although not herein illustrated, it will be understood that the needle-bar 28 carries a threaded needle at its forward end which cooperates with a threaded looper and a loop-spreader in the formation of a two-thread overedge chain-stitch in the manner disclosed in my prior patent. Also, as disclosed in theabove patent, the looper is actuated by connections with the reciprocating needlebar and the loop-spreader is actuated by suitable connections with the shaft 2 including the pitman 29, as seen in Fig. l, which embraces an eccentric on the shaft 2. Reference may be had to the above referred to patent for a complete description of this structure and the operation thereof.

Upon operation of thedisclosed machine, the shaft 2 is rotated which, in turn, imparts actuation to all of the machine mechanisms. It will be apparent that at normal operating speeds, which are in the order of 4,000 stitches per minute, undesirable vibrations will be set up in the machine due to dynamic unbalance particularly of the needle-bar mechanism. To overcome this vibration there is provided counterbalancing means comprising counterweights 30 and 31 xed to the balance-wheel 6 and beltpulley 7, respectively, and an independently actuated counterweight 32. The counterweight 32 is adjustably fixed by means of a set-screw 33 to a generally vertically arranged balancing-:rod 34 that extends through a bore in a hub member 35 and is normally fixed therein in adjusted position by a set screw 36. The hub 35 is provided with a sleeve-like portion 37 in which is formed a second bore arranged normal to the first bore and which bore loosely receives the pivot rod 13. The hub is held against sliding movement on the pivot rod 13 by collars 38. Intermediate the hub 35 andthe counterweight 32, the balancling-rod 34 slidably extends through a. bore formed in a block 3.9, which block includes a strap portion 40 that embraces an eccentric 41 on the shaft 2 and xed thereto by a set-screw 42. Thus,- as the shaft 2 is rotated, the eccentric 41 acting through the block 39 will swing the balancing-rod and the counterweight 32 carried thereby about the pivot rod 13 as an axis.

The dynamic etfectof'the counterweight 32, as will be obvious, is dependent upon the mass thereof, the eccentricity of the eccentric 41 which determines the arc through which it will be swung, and the radius of the arc. It should be noted that the rod 34 will also contribute to the. balancing of the machine. The optimum mass of the counterweight 32 and eccentricity of the eccentric 41 are predetermined and final adjustments of the counter-balancing effect may be secured by varying the radius of the arc through which the counterweight is swung by adjusting the same relative to the rod 34 or adjusting the rod relative to the hub 35.

In the construction disclosed it should be noted that the counterweight 32 is located closely adjacent the needle-bar whereas the rod 34 extends substantially through the area of the other moving elements of the machine. Such an arrangement tends to reduce the effects of any couple produced between the unbalanced and counter-balancing elements due to the dynamics of the same during operation. It has been found that in machines constructed as illustrated, the optimum setting of the eccentric 41 is at about 30 out of phase with respect to the needle-bar 28 rather than directly counter to the same, and that the balance of the machine can be substantially improved by the disclosed arrangement.

In addition, in machines as illustrated, the balancing expedient herein disclosed can be applied to existing machines. The only modifications necessary are to substitute for the normally provided pivot stud for the feed bell-crank lever, a pivot rod as 13 which is adapted to receive the sleeve-portion of the hub 35 of the balancing means, and to provide the new elements as required for the balancing means.

Access may be had to the screws 33 and 36 for adjusting the counterweight and to other internal mechanism of the machine through an aperture 43 in the rear of the frame 1, as more clearly seen in Figs. 2 and 3, The aperture 43 is closed by a cover plate 44 that is secured to the frame in oil-tight relation by screws 45.

Numerous alterations of the structure herein disclosed will suggest themselves to those skilled in the art. However, it is to be understood that the present disclosure relates to a preferred embodiment of my invention which is for purposes of illustration only and not to be construed as a limitation of the invention. All such modifications which do not depart from the spirit of the invention are intended to be included Within the scope of the appended claims.

Having thus described my invention, what I claim herel. In a sewing machine having a frame, a rotary shaft journaled in said frame, a pivot rod secured in said frame generally parallel to said rotary shaft, feeding mechanism comprising a feed actuating element on said rotary shaft, a feed-actuating lever mounted on said pivot rod for oscillation about the same, and operative connections between said feed-actuating element and said lever for imparting oscillation to said lever upon rotation of said shaft, stitching mechanism comprising a needle-bar arranged upon the opposite side of said shaft from said pivot-rod, and mounted in said frame for longitudinal reciprocation in a direction normal to said shaft, a stitching mechanism actuating element on said rotary shaft, and operative connections between said needle-bar and said stitching mechanism actuating element to impart reciprocation to said needle-bar upon rotation of said shaft, and means for dynamically balancing the machine comprising eccentric weights carried by said rotary shaft and an independently actuated counterweight comprising a hub pivotally mounted on said pivot rod, a balancing rod fixed in said hub for longitudinal adjustment relative to the same, a Weight of predetermined mass fixed to said balancing rod for adjustment longitudinally thereof, a balancing means actuating element fixed to said shaft, and a block mounted upon the balancing rod intermediate the hub and the counterweight, said block being operatively connected to the balancing means actuating element for imparting oscillation to said balancing rod about the pivot rod upon rotation of said shaft.

2. In a sewing machine having a frame including a vertically disposed standard, a rotary shaft journaled in said standard transversely thereof, a pivot rod carried by said standard and arranged generally parallel to and vertically below said rotary shaft, feeding mechanism comprising a feed-actuating element on said rotary shaft, a feed-actuating lever mounted on said pivot rod for oscillation about the same, and operative connections between said feed-actuating element and said lever for imparting oscillation to said lever upon rotation of said shaft, stitching mechanism comprising a horizontally disposed needlebar mounted for longitudinal reciprocation in said standard, a stitching mechanism actuating element on said rotary shaft, and, operative connections between said needle-bar and said stitching mechanism actuating element to impart reciprocation to said needle-bar upon rotation of said shaft, and means for dynamically balancing the machine comprising eccentric weights carried by said rotary shaft and an independently actuated counterweight comprising a hub pivotally mounted on said pivot rod, a balancing rod fixed in said hub for longitudinal adjustment relative to the same and being arranged generally vertically within the standard, a weight of predetermined mass fixed to said balancing rod for adjustment longitudinally thereof, a balancing means actuating element fixed to said rotary shaft, and means operatively connecting the balancing means actuating element to said balancing rod at a point intermediate the hub and the counterweight for imparting oscillation to said balancing rod about the pivot rod upon rotation of said shaft.

3. A balancing assembly for a sewing machine having a frame including a vertically disposed standard, a rotary shaft journaled in said standard transversely thereof, a pivot rod carried by said standard and arranged generally parallel to and vertically below said rotary shaft, feeding mechanism comprising a feed-actuating element on said rotary shaft, a feed-actuating lever mounted on said pivot rod for oscillation about the same, and operative connections between said feed-actuating element and said lever for imparting oscillation to said lever upon rotation of said shaft, stitching mechanism including a needle-bar mounted for longitudinal reciprocation in said standard, a stitching mechanism actuating element on said rotary shaft, and operative connections between said needle-bar and said stitching mechanism actuating element to impart reciprocation to said needle-bar upon rotation of said shaft, said balancing assembly comprising a hub adapted to be pivotally mounted upon said pivot rod, a balancing rod adapted to be xed in said hub for longitudinal adjustment relative to the same and to be arranged generally vertically within the standard, a weight of predetermined mass adapted to be fixed to said balancing rod for adjustment longitudinally thereof, a balancing means actuating element adapted to be mounted on said rotary shaft, and means for operatively connecting the balancing means actuating element to said balancing rod at a point intermediate the hub and the counterweight for imparting oscillation to said balancing rod about the pivot rod upon rotation of said shaft.

References Cited in the file of this patent UNITED STATES PATENTS 2,363,807 Rubel Nov. 28, 1944 

